1mlib_SignalCepstral_F32(3MLmIeBd)iaLib Library Functimolnisb_SignalCepstral_F32(3MLIB)
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NAME

6       mlib_SignalCepstral_F32 - perform cepstral analysis
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SYNOPSIS

9       cc [ flag... ] file... -lmlib [ library... ]
10       #include <mlib.h>
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12       mlib_status mlib_SignalCepstral_F32(mlib_f32 *cepst,
13            const mlib_f32 *signal, void *state);
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DESCRIPTION

17       The mlib_SignalCepstral_F32() function performs cepstral analysis.
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20       The basic operations to compute the cepstrum is shown below.
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22               +-----------+      +--------+       +-----------+
23               |  Fourier  |      |        |       |  Inverse  |
24         ----->|           |----->| log|*| |------>|  Fourier  |----->
25          x(n) | Transform | X(k) |        | X'(k) | Transform | c(n)
26               +-----------+      +--------+       +-----------+
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30       where  x(n)  is the input signal and c(n) is its cepstrum. In mathemat‐
31       ics, they are
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33                N-1                2*PI*k*n
34         X(k) = SUM x(n) * exp(-j*----------)
35                n=0                   N
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37         X'(k) = log|X(k)|
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39                 1  N-1                2*PI*k*n
40         c(n) = --- SUM X'(k) * exp(j*----------)
41                 N  n=0                   N
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45       Since X'(k) is real and even (symmetric), i.e.
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47         X'(k) = X'(N - k)
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51       the c(n) is real and the equation becomes Cosine transform.
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53                 1  N-1              2*PI*k*n
54         c(n) = --- SUM X'(k) * cos(----------)
55                 N  n=0                 N
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59       The cepstral coefficients in LPC is a special case of the above.
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62       See Digital Signal Processing  by  Alan  V.  Oppenheim  and  Ronald  W.
63       Schafer, Prentice Hall, 1974.
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66       See  Fundamentals  of  Speech Recognition by Lawrence Rabinerand Biing-
67       Hwang Juang, Prentice Hall, 1993.
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PARAMETERS

70       The function takes the following arguments:
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72       cepst     The cepstral coefficients.
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75       signal    The input signal vector.
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78       state     Pointer to the internal state structure.
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RETURN VALUES

82       The function returns MLIB_SUCCESS if successful. Otherwise  it  returns
83       MLIB_FAILURE.
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ATTRIBUTES

86       See attributes(5) for descriptions of the following attributes:
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91       ┌─────────────────────────────┬─────────────────────────────┐
92       │      ATTRIBUTE TYPE         │      ATTRIBUTE VALUE        │
93       ├─────────────────────────────┼─────────────────────────────┤
94       │Interface Stability          │Committed                    │
95       ├─────────────────────────────┼─────────────────────────────┤
96       │MT-Level                     │MT-Safe                      │
97       └─────────────────────────────┴─────────────────────────────┘
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SEE ALSO

100       mlib_SignalCepstralInit_F32(3MLIB), mlib_SignalCepstralFree_F32(3MLIB),
101       attributes(5)
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105SunOS 5.11                        2 Mar 2007    mlib_SignalCepstral_F32(3MLIB)
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